Mastering OpenSSH – Part 2: How to secure OpenSSH

Posted by Raffael on 04/09/201305/01/2013 Posted in Linux, Tutorials Tagged change openssh port, how to secure openssh, openssh, openssh disable root login, openssh security, openssh security advisory, openssh security vulnerabilities

Now that we have installed the OpenSSH server on the Linux box and thereafter successfully connected using Putty, using SSH under Linux and using OpenSSH for Windows, we should go in this (second) part of the series on how to basically secure the OpenSSH server.
Change default port
First, we should change the port on which the server is running OpenSSH. But why? This is a classic case of security through obscurity. Theoretically this does not change the level of security. Practically, however, you can recognize that the number of attacks to the SSH server falls. This is because many attackers only scan on port 22, the default SSH port. If we change the port, we get out of the scanners scope. Sure, someone who has specifically chosen our server as an attack object, can still perform a port scan, but nevertheless it’s worth the effort, to exclude the just mentioned “haphazard” […]

Mastering OpenSSH – Part 1: Installing the OpenSSH server

Posted by Raffael on 03/10/201302/27/2015 Posted in Linux, Tutorials Tagged how to establish a ssh connection, mastering ssh, openssh, openssh beginners, openssh for windows, openssh tutorial, putty tutorial, ssh

When it comes to secure connections between two computers, SSH (SSH = Secure Shell) is the drug of choice. Thus for example you can remotely control your home- or web-server by an encrypted connection via SSH. How to install the OpenSSH server (software) on Linux (Ubuntu) and establish and secure the connections, is what I want to show to you in the following series of articles.
As an example scenario, we assume that we have a Linux machine which acts as a server and two computers, one with Ubuntu Linux and one running Windows 8, which represent our clients.
OpenSSH server installation
The first step is to download the server software. The SSH client (for connecting the server with another PC/server for example) can be installed as well if needed.

sudo apt-get update
sudo apt-get install openssh-server openssh-client

After the installation of the OpenSSH server you may need to start the service manually. This can be […]

How to activate USB mass storage and developer options on CyanogenMod

Posted by Raffael on 03/05/201311/03/2017 Posted in News & Apps, Tutorials Tagged Android, CaynogenMod, CM 10.1, CM 10.1 developer options, CM 10.1 usb debugging, CM 10.1 usb mass storage, Galaxy S2, Motorola Defy

For over three years I’m a user of Android smartphones. At first with Motorola Defy, then Samsung’s Galaxy S2. What both of these devices have in common, is the fact, that both were not running the original ROM for a long time. Too much trash, too much unnecessary, pre-installed software and really to less updates.
Both devices got the CyanogenMod-ROM, one of the most famous mods for Android devices. And because I like to be up to date and also like to try out experimental features, I flash my Samsung Galaxy S2 regularly with the so called nightly builds. (Nightly-Builds = daily updated version directly from the developers. Bleeding edge but not always 100% stable.)
No products found.With the latest CyanogenMod version (10.1), two features have disappeared, so far. On the one hand the possibility to use the phone as a mass storage device on your PC and on the other hand […]

Vim tutorial for beginners

Posted by Raffael on 03/01/201303/07/2013 Posted in Linux, Tutorials Tagged vi, vim, vim basics, vim beginners tutorial, vim copy paste, vim tutorial

vim screenshot Vim is an open source text editor that runs on Linux, MacOSX, Windows and many other operating systems. If I had to describe it in just one word, then the first thing I can think of would be “powerful”. Vim supports syntax highlighting for really almost any format and has got many other extras.
But “powerful” also describes the learning curve, because Vim can be fully controlled via the keyboard. There are tons of commands and shortcuts you can learn. But however, if you once learned how to handle Vim it is a wonderful tool. Just the fact that Vim can actually be found on nearly any Linux system, no matter where and under what distribution you are currently working, is a good reason to learn at […]